Ethnic and sex differences in bone marrow adipose tissue and bone mineral density relationship

Abstract

Summary The relationship between bone marrow adipose tissue and bone mineral density is different between African Americans and Caucasians as well as between men and women. This suggests that the mechanisms that regulate the differentiation and proliferation of bone marrow stromal cells may differ in these populations. Introduction It has long been established that there are ethnic and sex differences in bone mineral density (BMD) and fracture risk. Recent studies suggest that bone marrow adipose tissue (BMAT) may play a role in the pathogenesis of osteoporosis. It is unknown whether ethnic and sex differences exist in the relationship between BMAT and BMD. Methods Pelvic BMAT was evaluated in 455 healthy African American and Caucasian men and women (age 18–88 years) using whole-body T1-weighted magnetic resonance imaging. BMD was measured using whole-body dual-energy X-ray absorptiometry. Results A negative correlation was observed between pelvic BMAT and total body BMD or pelvic BMD (r=−0.533, −0.576, respectively; P<0.001). In multiple regression analyses with BMD as the dependent variable, ethnicity significantly entered the regression models as either an individual term or an interaction with BMAT. Menopausal status significantly entered the regression model with total body BMD as the dependent variable. African Americans had higher total body BMD than Caucasians for the same amount of BMAT, and the ethnic difference for pelvic BMD was greater in those participants with a higher BMAT. Men and premeno-pausal women had higher total body BMD levels than postmenopausal women for the same amount of BMAT. Conclusions An inverse relationship exists between BMAT and BMD in African American and Caucasian men and women. The observed ethnic and sex differences between BMAT and BMD in the present study suggest the possibility that the mechanisms regulating the differentiation and proliferation of bone marrow stromal cells may differ in these populations.

Comparison of the Relationship Between Bone Marrow Adipose Tissue and Volumetric Bone Mineral Density in Children and Adults

“…This cellular relationship is supported by recent studies analyzing BMD and BMAT in large cohorts of young and old adult populations (7, 11–15). A recent study by Shen et al (2012) in young adults who had reached peak bone mass and older adults undergoing potential bone loss, a similar inverse relationship was shown between BMD and BMAT (13).…”

“…Furthermore, the results of this analysis were compared to adult populations to determine the vBMD and BMAT relationship present throughout the lifespan. Since the areal BMD and BMAT relationship in the adult population has been previously reported (13, 18), this paper focuses on comparing this relationship in children and adults.…”

Comparison among T1-Weighted Magnetic Resonance Imaging, Modified Dixon Method, and Magnetic Resonance Spectroscopy in Measuring Bone Marrow Fat

“…The threshold for BMAT segmentation on T1-weighted MRI was set at the same level as subcutaneous adipose tissue on the grey scale. The reader first sets the threshold that best segments subcutaneous adipose tissue on the grey scale [2–4, 17–19], then that threshold is used in the same image to segment BMAT. In the SliceOmatic software package, the segmentation threshold can be freely adjusted and the analyst can view the “preview” of subcutaneous adipose tissue segmentation, which is transparently overlaid on the grey image.…”

Marrow Adipose Tissue: Trimming the Fat

“…Combined, this would predict 1142+/−410 cm 3 of total MAT, equivalent to 1.03+/−0.37 kg (fat density = 0.9 g/cm 3 ). Indirect MRI-based techniques concur, revealing that the amount of total MAT in the skeleton of an average size human is ~ 1.35 kg (ranging from 0.5 to 3 kg) [8,10,11], accounting for approximately 8% of total fat mass. Depending on peripheral fat volume, this proportion can range from as low as 1% to as high as ~ 30% [2,12].…”